ABSTRACT
Wound healing requires a substantial amount of moisture for faster recovery. Completely hydrophobic or hydrophilic biomaterials are not suitable to be applied for cell growth in wounded areas. The study aimed to prepare a nanofibrous scaffold from the blend of a solution of hydrophobic PLA and a solution of hydrophilic gelatine. The stability of the blend was achieved using a surfactant and an electrospun nanofibrous scaffold was made out of the solution. The optimum composition of gelatine and PLA to make a scaffold of uniform fibre diameter was achieved with the help of conductivity, viscosity and FESEM analysis. The optimum scaffold was characterised by TGA, DSC and XRD analysis. The water contact angle of the optimum sample was observed at 27°. The blended scaffold was found non-toxic to cells and showed a 30% faster healing of wounds in the rat model test compared to the healing rate of the PLA scaffold or the gelatine scaffold alone. The histological assay also supported the blend scaffold as an encouraging material for tissue regeneration.
ABSTRACT
The research involves developing eco-friendly polymer composites by combining synthetic unsaturated polyester resin (UPR) with treated and untreated leather fibers (LF), cow hair fibers (CHF), and chicken feather fibers (CFF). By using these natural fibers instead of synthetic polymer, we aim to reduce the environmental impact while finding new purposes for waste materials from the poultry and tannery industries which would otherwise end up in garbage. The fibers were incorporated into the resin matrix at various weight percentages such as 2, 5, 7, 10, 12, and 15 % (w/w). Additionally, the properties of composites were improved by the addition of different types of inorganic nanoparticles, like CaCO3, Al2O3, and ZnO to the UPR matrix. These composites where inorganic materials were added as filler revealed better results than the neat composites. The composites showed the maximum overall mechanical properties in the bending modulus (BM), bending strength (BS), tensile modulus (TM), and tensile strength (TS) when 5 % of cow hair and chicken feather mixed fiber was used and ZnO was added as filler compared to the other composites. The highest values 4400.415, 68.91, 1788.74, and 34.95 N/mm2 of BM, BS, TM, and TS respectively, were found for the CFF + CHF + UPR + ZnO composite. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) supported mechanical rather than chemical connections between fiber and UPR. Ionizing gamma radiation-modified fiber exhibited superior tensile characteristics when 5 % of cow hair and chicken feather mixed fiber was used.
ABSTRACT
During the past decades, microplastics (MPs) have become an emerging concern due to their persistence and potential environmental threat. MP pollution has become so drastic that it has been found in the human food chain, breast milk, polar regions, and even the Himalayan basin, lake, etc. Inflammation, pulmonary hypertension, vascular occlusions, increased coagulability and blood cell cytotoxicity, disruption of immune function, neurotoxicity, and neurodegenerative diseases can all be brought on by severe microplastic exposure. Although many MPs studies have been performed on single environmental compartments, MPs in multi-environmental compartments have yet to be explored fully. This review aims to summarize the muti-environmental media, detection tools, and global management scenarios of MPs. The study revealed that MPs could significantly alter C flow through the soil-plant system, the structure and metabolic status of the microbial community, soil pH value, biomass of plant shoots and roots, chlorophyll, leaf C and N contents, and root N contents. This review reveals that MPs may negatively affect many C-dependent soil functions. Different methods have been developed to detect the MPs from these various environmental sources, including microscopic observation, density separation, Raman, and FT-IR analysis. Several articles have focused on MPs in individual environmental sources with a developed evaluation technique. This review revealed the extensive impacts of MPs on soil-plant systems, microbial communities, and soil functions, especially on water, suggesting possible disturbances to vital ecological processes. Furthermore, the broad range of detection methods explored emphasizes the significance of reliable analytical techniques in precisely evaluating levels of MP contamination in various environmental media. This paper critically discusses MPs' sources, occurrences, and global management scenarios in all possible environmental media and ecological health impacts. Future research opportunities and required sustainable strategies have also been suggested from Bangladesh and international perspectives based on challenges faced due to MP's pollution.
Subject(s)
Environmental Monitoring , Microplastics , Microplastics/analysis , Environmental Monitoring/methods , Water Pollutants, Chemical/analysis , Soil Pollutants/analysisABSTRACT
The utilization of natural fiber reinforced polymer composites is growing fast in numerous sectors. In this study, the effect of the addition of short date palm mat (DPM) fibers in polystyrene matrix on the physico-mechanical and thermal properties were studied. Short DPM fiber reinforced polystyrene composites were produced by compression moulding process and the fiber content was 5, 10, 15, 20 and 25 wt%. Physico-mechanical and thermal properties were examined. Scanning electron microscopy (SEM) and Fourier-transform infrared (FT-IR) analysis of the composites were also done. The findings from the investigates exposed that the composites with 10 % fiber content showed improved mechanical and thermal characteristics as compared to other composites. The morphological analysis also supported the results where good interfacial bonding among fiber and polystyrene matrix was found for the composites with 10 % fiber content. The optimized (10 % fiber content) composites were exposed to gamma radiation (2.5-7.5 kGy) and the best result was found at 5.0 kGy radiation dose. Degradation of gamma irradiated composites was conducted in four different media such as water, acid, base, and brine.
ABSTRACT
Jute fabrics and unidirectional jute fiber reinforced polypropylene (PP) and linear low density polyethylene (LLDPE) based composites were prepared successfully by compression molding technique. The unidirectional jute fiber was treated with Reactive Orange HB® and Deep Blue LW® dye to investigate physico-mechanical properties. The Reactive Orange HB® treated composites showed relatively better mechanical properties than the Deep Blue LW® treated composites. The jute fiber-based composites showed higher mechanical properties than that of jute-based fabrics. The polypropylene-based composites showed better mechanical properties than that of LLDPE. The variations of mechanical properties were also observed. The highest mechanical properties were at -18 °C and lowest at 50 °C. Water absorbent, SEM and FT-IR analysis of the composite was also carried out.
ABSTRACT
The stem bark of Polyalthia simiarum has yielded a new bisnor-type clerodane diterpenoid, 2-oxo-14,15-bisnor-3,11E-kolavadien-13-one (1), and three previously known clerodane derivatives, kolavenic acid (2), 16beta-hydroxycleroda-3,13(14)Z-dien-15,16-olide (3), and 16-oxocleroda-3,13(14)E-dien-15-oic acid (4). The structures of these compounds were unambiguously determined by extensive NMR studies as well as by comparison with related compounds. Till now this is the second report of the occurrence of any unusual C-18 clerodane diterpenoid from nature. The crude light petroleum extract and the purified compound 3 demonstrated moderate free radical scavenging activity with IC50 values of 21.5 and 23.5 microg/mL, respectively.
